It ain’t rocket science but it ain’t avionics now either.
The avionics engineer used to be someone who could repair anything radio. Now, if your GTN750 packs up, send it back to Garmin is the only option.
When you look at the installation of these new avionics, it is all computer network cables. Half the time spent on installing new avionic suites is down to making all the bits speak to each other, set-up pages, etc.
Now, far be it for me to say but the licensing system for avionic engineers is so far behind the CAA / EASA should throw it all away.
What does it need to install 8.33 kit?? Bugger all really.